1) Field of the Invention
The invention relates to a boiler having a combustion chamber with a heat insulating block.
2) Description of Related Art
German Patent Application Publication No. DE 34 25 667 A1 discloses a boiler having primary and secondary heat exchangers, wherein the secondary heat exchanger is located behind the combustion chamber when viewed in the axial direction, hence a compact design is not possible because of the necessary burn-up length.